Many different types of container to be filled with products in the form of liquid or powder are currently available.
One type of container is collapsible and comprises two flexible side walls and a bottom wall, which walls are interconnected along a connecting portion to form a compartment whose volume is dependent on the relative position of the walls.
This type of container can, before filling, be in a plane and sealed state. This makes it possible to sterilise the compartment of the container in connection with manufacture and, with maintained sterility, distribute the container to a filling plant, such as a dairy.
A container of the type described above is known from WO99/41155 which also discloses a device for filling the container.
Said device comprises a nozzle which is insertable into a filling duct of the container, said filling duct being opened by cutting or a similar operation in connection with filling of the container.
During the actual filling process, said nozzle is thus inserted into the filling duct, after which a product valve is opened to supply the desired product quantity to the compartment of the container through said nozzle. The compartment will then take a volume which substantially corresponds to the volume of the supplied product. The filling process ensures that intrusion of air into the compartment is prevented or at least minimised.
The filling device disclosed in WO99/41155 comprises more specifically a nozzle which is made of an elastic material, such as silicone rubber. The nozzle has an end portion which tapers towards an outlet in the form of a gap in the lower end surface of the end portion.
The nozzle is self-closing, which means that the edge portions which define said gap engage each other in the absence of application of outer forces.
During the filling process, the nozzle is, as mentioned above, inserted into the filling duct of the container, after which the product is supplied to the compartment through said nozzle. The product pressure will act to open the nozzle and at the same time to establish a seal between the nozzle and the walls of the filling duct to ensure that air does not enter the container.
Increasing demands are placed on the efficiency of filling devices of the type described above and, thus, also on the speed at which the device allows filling of an individual container.
Faster filling can be achieved with an increased product flow velocity, which results in a higher product pressure. It has been found that an increased product pressure may in some cases result in the product being pressed out of the compartment of the container between the nozzle and the walls of the filling duct. For obvious reasons, this causes problems in maintaining a hygienic environment in the filling device.
There is thus a need for a filling device which allows efficient and rational filling of containers of a collapsible type.